package com.kitty.record.kittyio.nio.one;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

/**
 * @Description
 * @Author SHEN
 * @Date 2021/2/18
 */
public class Server {

    public static void main(String[] args) throws IOException {

        //1.获取通道
        ServerSocketChannel ssChannel = ServerSocketChannel.open();

        //2.切换非阻塞模式
        ssChannel.configureBlocking(false);
        //3.绑定连接
        ssChannel.bind(new InetSocketAddress(9999));
        //4.获取选择器
        Selector selector = Selector.open();
        //5.将通道注册到选择器上，并指定“监听接受事件”
        ssChannel.register(selector, SelectionKey.OP_ACCEPT);
        //6.轮询获取选择器上的已经准备就绪的事件
        while (selector.select() > 0){

            System.out.println("轮一轮");
            //7. 获取当前选择器中所有注册的“选择键(已就绪的监听事件)”
            Iterator<SelectionKey> it = selector.selectedKeys().iterator();

            while (it.hasNext()){
                //8. 获取准备“就绪”的是事件
                SelectionKey sk = it.next();
                //9. 判断具体是什么事件准备就绪
                if(sk.isAcceptable()){
                    //10. 若“接收就绪”，获取客户端连接
                    SocketChannel sChannel = ssChannel.accept();
                    //11. 切换非阻塞模式
                    sChannel.configureBlocking(false);
                    //12. 将该通道注册到选择器上
                    sChannel.register(selector, SelectionKey.OP_READ);
                }else if(sk.isReadable()){
                    //13. 获取当前选择器上“读就绪”状态的通道
                    SocketChannel socketChannel = (SocketChannel) sk.channel();

                    //14.读取数据

                    ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
                    int len = 0;

                    while((len = socketChannel.read(byteBuffer)) > 0){
                        byteBuffer.flip();
                        System.out.println(new String(byteBuffer.array(),0,len));
                        byteBuffer.clear();
                    }
                }
                //15. 取消选择键 SelectionKey
                it.remove();
            }

        }

    }

}
